Plenty to consider
When looking at this there is a broad spectrum of considerations that may not have been looked at. What do you want out of a long term relationship down the road and can she fulfill that? Let's say you fall madly in love with her and want to get married and have kids. How will you feel about introducing her to your parents and friends? Are you prepared for that possibity? There are a lot of external factors that will come into play when you invest deeper. I'm not trying to be negative...just trying to get you to look further down the road at other issues which may take the forefront when NRE wears off.
Mono-Poly can work and can be wonderful but I recommend you really look at your needs in the future as a couple before investing more of yourselves.
Playing the Game of Life with Monopoly rules.
Monogamy might just be in my genes
Poly Events All Over